Exercise machines having alternating reciprocating foot supports configured to traverse or travel about a closed path to simulate a striding, running, walking, and/or a climbing motion for the individual using the machine are well known, and are commonly referred to as elliptical exercise machines or elliptical cross-trainers. In general, an elliptical or elliptical-type exercise machine comprises a pair of reciprocating foot supports designed to receive and support the feet of a user. Each reciprocating foot support has at least one end supported for rotational motion about a pivot point (e.g., a pivot end), with the other end supported in a manner configured to cause the reciprocating foot support to travel or traverse a closed path, such as a reciprocating elliptical or oblong path or other similar geometric outline (e.g., a closed path end). Therefore, upon operation of the exercise machine, each reciprocating foot support is caused to travel or traverse the closed path, thereby simulating a striding motion of the user for exercise purposes. Typically, the reciprocating foot supports are configured to be out of phase with one another by approximately 180 degrees in order to simulate a proper and natural alternating stride motion.
An individual may utilize an elliptical exercise machine by placing his or her feet onto the reciprocating foot supports. Once standing on the foot supports, the individual may then actuate the exercise machine for any desired length of time and at any desired pace to cause the reciprocating foot supports to repeatedly travel their respective closed paths, which action effectively results in a series of strides achieved by the individual to obtain a desired level of exercise, such as distance travelled or calories burned. Exercise achieved using an elliptical exercise machine is particularly favored by individuals seeking aerobic exercise that causes little or no physical impact.
One type of elliptical exercise machine includes a roller carried at the closed path end of the reciprocating foot support. The roller is supported by a track member. Opposing ends of the track member define a maximum travel distance for the reciprocating foot support. The roller usually does not contact either of the opposing ends of the track member when the user is operating the elliptical exercise machine in a normal stride. However, the roller contacts at least one of the ends of the track member when longer than normal strides are taken. This contact can result in high impact forces that create additional wear and stress in the machine and potential discomfort for the user.
An example elliptical exercise machine that includes a track member is disclosed in U.S. Pat. No. 7,618,350 issued to William T. Dalebout et al. and assigned to Icon IP, Inc. In this patent, an elliptical exercise machine includes a pair of track members within which rollers connected to the reciprocating foot supports move during operation of the machine. The track members define straight tracks that support the rollers. Similar elliptical exercise machines can also be found in U.S. Pat. Nos. 5,993,359; 6,422,977; and 7,468,021 and U.S. Patent Publication Nos. 2010/0041522 and 2007/0054779.